I think the Revenge of the Sith's worst lines were when Anakin and Padme went on about how blind and in love they were and that they were blind because they were in love and they were in love because they were blind and that's why they couldn't see how oily Padme's face was.

1. Rosebud2. Use the force, Luke3. Say hello to my little friend4. And don't call me Shirley5. You had me at 'hello'6. You're going to need a bigger boat7. The snozzberries taste like snozzberries8. If God would have wanted you over that obstacle, he would have miracled your ass over it, isn't that right private Pyle?9. Flash, I love you, but we only have 13 hours to save the earth10. Biatch better have my money11. Go check it out (Nicholson in "The Shining")12. Frankly my dear, I don't give a damn13. You fargin iceholes

there were some pretty bad lines of dialogue in the Expendables 2. I watched the first one and enjoyed it as mindless entertainment, but the second one had so many cringe worthy moments of dialogue it even made the action sequences terrible.

"By the powers vested in me, I now pronounce you man and knife" -Expendables 2